This invention relates to door screens. More specifically, this invention relates to horizontally movable door screens rotatably mounted on a take-up shaft and capable of being rolled and unrolled from a vertically oriented storage member.
There are a number of examples in the prior art of rolling screens for use with doors. In general, these screens consist of a latch member and a vertically oriented take-up roll located in front of a door frame member. The latch member tends to be vertically oriented on the door frame member opposite the take-up roll. The take up roll has a screen rotatably mounted on it, which can be extended and retracted according to the users needs. Though functional, the prior art screens do have some significant problems.
The most common problem is that many screens are open at the upper and lower edges. With these designs the screen is only connected to the latch member and the take-up shaft, thus leaving the upper and lower portion of the screen open. This allows insects and other debris to enter the building through the screen, which decreases the effectiveness of the screen.
Some designs solve this problem by placing guide rails on the top and bottom of the door opening. The screen moves within these guide rails as it is extended across the opening, thus creating a better seal. However, the screen is easily dislodged from the typical guide rail. Minimal twisting of the screen as it is moved through the screen door assembly can cause the screen to be removed from the rails, thus making use of the screen more difficult.
Another problem comes with the latch mechanism for the screen. Latching a screen in place often involves time consuming steps. A typical screen will have either a handle or hook-and-eye latch mechanism. A handle latch will have a handle portion that locks within a latch portion. This can be done by placing a retainer mechanism, or latch portion, for the handle portion within a vertical member. The vertical member will be located on the opposite side of the opening from the take-up shaft. These latch mechanisms can be tedious to use and are prone to breaking. In addition, latching and unlatching these assemblies can be time consuming.
The hook-and-eye latch requires holes, or eyes, within the screen to be aligned with hooks located on the vertical member. The hooks, which operate as the latch portion, are then placed through the eyes to hold the screen in place. Again, this process can be tedious and time consuming. The inconvenience of aligning the hooks and eyes every time the screen must be closed discourages use of the screen.
A further problem with prior rolling screen designs is that there is no way for a user to easily adjust the winding speed of the screen. To change the speed at which the screen winds, the torque on an internal spring must be changed. To do this on most screens, the take-up shaft must be disassembled to gain access to the spring. Even if access is gained, there is often no mechanism for adjusting the tension of the spring within the take-up shaft. The process of changing the tension on the spring is too difficult for an average consumer to do, so as a practical matter the speed of winding can not be changed on a typical rolling screen. Additionally, on prior art screen doors it is possible to over tension the coil spring causing a dangerous high speed return of the handle portion.
Finally, most rolling screens require a large housing to conceal the take-up shaft and screen. The vertical members, if used, are much smaller than the take-up shaft housings, so the door opening will not be symmetrical. In addition, the large housing and vertical member are very different in size from normal door moldings, so they tend to make the building unattractive. If guide rails are used on the top and bottom, these again detract from the appearance of the door opening. The lower rail can also create a tripping hazard if it is unnoticed by a user. As a result of these problems, many people will choose not to use rolling screens for aesthetic and safety reasons.
The aforementioned problems are overcome by the present invention wherein a screen door is provided which includes a take-up shaft attached to an adjustable gear assembly for winding the spring, a screen rotatably wound on the take-up shaft, a screen case which encloses the screen and take-up shaft, a handle, preferably with endcaps, attached to the screen, and upper and lower guide rails possibly containing a unique latch mechanism.
The upper and lower guide rails may have ribs for guiding the screen as it is extended. The endcaps of the handle, which should be wider than the opening for the screen in the guide rails, ride along the ribs as the handle is pulled from the screen case. Since the endcaps are wider than the opening in the guide rails, the handle, and thus the screen, is positively retained within the rails as the screen is extended.
At the end of the guide rails, the ribs are removed. In this configuration when the handle reaches the end of the rails, the endcaps slip off the ribs. The endcap at the top of the handle then rests on a shelf within the upper guide rail. This simple procedure latches the screen in place.
The take-up shaft is attached to a gear assembly with a front access hole. A simple tool, such as a hexagonal wrench, can be inserted into the gear assembly to adjust the tension on the spring attached to the take-up shaft. This will change the force on the spring and effect the speed with which the screen is retracted into the screen case when it is unlatched. The gear assembly also includes a clutch mechanism that limits the maximum torque applied to the spring by the gear assembly.
In addition, the screen case is preferably molded to have the appearance of a typical door molding. A similar molding may be placed opposite the screen case to give the appearance of a normal door casing. The mantle can also be molded in a similar manner. The upper guide rail will be added to or incorporated into the mantle.
The lower guide rail is incorporated into a typical doorsill, which reduces the risk of tripping over the guide rail when entering or leaving through the door.